International Motors, LLC (formerly Navistar International Corporation) is an American manufacturer of commercial vehicles and engines, established in 1986 as a successor to the International Harvester company. International Motors produces trucks under its own brand and buses under the IC Bus name. Since July 2021, the company has been a subsidiary of Traton, the heavy-vehicle division of the Volkswagen Group.

Headquartered in Lisle, Illinois, International Motors employs approximately 14,500 people worldwide as of 2024. The company maintains an extensive distribution network, with nearly 1,000 dealer outlets across the United States, Canada, Brazil, and Mexico, and over 60 dealers in 90 other countries. International Motors' product line includes a range of commercial trucks, from medium-duty Class 4 to heavy-duty Class 8 vehicles.

International Harvester (IH) was created in 1902 by the merger of McCormick Harvesting Machine Company, and Deering Harvester Company. In 1908, IH introduced the Auto Wagon, an early precursor to the pickup truck. Over the decades, IH became a diversified manufacturer, producing a wide range of vehicles from agricultural machinery to consumer-grade trucks and heavy-duty commercial vehicles. Notable products included the Farmall tractor, Cub Cadet lawn and garden equipment, and vehicles like the International Scout and International Travelall SUV. The company’s truck lineup ranged from light-duty vehicles (Light Line) to heavy-duty trucks. IH became a leading name in both agriculture and construction, further expanding with the development of the first sport-utility vehicles.

In the early to mid-1980s, IH faced financial struggles due to the poor agricultural economy and the lingering effects of the 1979–1980 strike. New chairman and CEO Louis W. Menk brought in a new management team, including president Donald Lennox, to oversee a restructuring process. As part of this reorganization, the company sold many of its divisions, including the Construction Equipment Division to Dresser Industries, the Solar gas turbine division to Caterpillar, and Cub Cadet lawn equipment to MTD Products. The company also entered into a 1983 supply agreement with Ford Motor Company, providing the 6.9L IDI diesel V8 for Ford's full-size trucks and vans, a move that continued until 2010.

In 1985, IH sold its Agricultural Division to Tenneco, the parent company of rival Case Corporation. The IHC name and logo became part of the sale, with Tenneco creating the Case IH brand. The remaining portions of the company, including the International Truck and Engine Divisions, rebranded as Navistar International Corporation on February 20, 1986. This new identity combined “Navi-” (for navigation) and “Star” (from multiple truck lines), and introduced an orange-red diamond logo. Navistar focused on trucks and engines, marking the beginning of a new era for the company.

In 1987, Navistar introduced the 8300, a second generation of the International S series, which was part of the “Thousand Series” trucks. These vehicles included Class 7/8 tractors and medium-duty 4000-series trucks, introduced in 1989. The Thousand-Series trucks featured improvements for better fuel economy, including aerodynamic hoods with faired-in headlamps, turn signals, and body-color grilles. After 1986, Navistar shifted to exclusively producing diesel-powered vehicles.

In 1990, International introduced the 9400, an aerodynamic Class 8 truck derived from the Transtar/Paystar cab, using a set-back front axle (to allow for a longer, sloped hood); the classic-style 9300 (the previous Transtar) continued. In 1991, the final remnant of International in the automotive segment was sold off, as the Scout and Light Truck parts business was sold to Scout/Light Line Distributors, Inc. The same year, Navistar became the parent company of a school bus manufacturer as it purchased one-third of American Transportation Corporation (AmTran).

Serving as a chassis supplier since the 1920s, Navistar gained significant market share in school bus production, acquiring AmTran entirely in April 1995. In 1994, the IDI diesel was replaced by the all-new T444E diesel V8. Sharing only displacement with its predecessor, the T444E introduced direct injection and standard turbocharging; the engine marked the introduction of the PowerStroke diesel branding for Ford vehicles. In 1998, following a decline in demand for COE trucks in North America, the 9800 was discontinued and production moved to Brazil.